1. Field of the Invention
The present invention relates to an attachment for power tools and, in particular, to a device for actuating a reciprocating saw from a hand drill.
2. Description of the Related Art
Reciprocating saws are frequently used by contractors and the like for various cutting applications. Unfortunately, such saws are typically heavy and inconvenient to operate. In order to reduce the inconvenience associated with these saws, a variety of attachments have been developed for converting a rotary power tool, such as a drill, into a reciprocating saw. However, many of these attachments would require a power tool having a front portion specially shaped for receiving the attachment. Moreover, most reciprocating saw attachments are connected to the power tool by a rotating spindle. The rotation of the spindle makes it necessary for the operator to grip the saw attachment during operation. Should the operator loose his or her grip, the attachment will rotate in an unrestrained fashion, thereby potentially causing an injury.
Therefore, there is a need for a drill powered reciprocating saw having an automatic safety mechanism that will disengage the saw""s drive mechanism and prevent the saw from rotating should the operator loose his or her grip on the saw housing, or should the drill be activated without the saw housing being gripped by the operator.
U.S. Pat. No. 1,793,053 discloses a saw which attaches to a potable hand tool, such as a drill. The saw uses a gear and belt drive mechanism to convert the rotary motion of the drill into reciprocating motion.
U.S. Pat. No. 2,240,755 discloses a power tool using a gearing mechanism to convert the rotary motion of a drill to a reciprocating motion.
U.S. Pat. No. 2,621,685 discloses a hand carried powered tool which uses a gear and flywheel mechanism to convert the rotary motion of a motor into reciprocating motion for a saw blade. The tool includes a work-rest for providing support against a work surface.
U.S. Pat. No. 2,631,619 discloses a reciprocating saw tool attachment which converts the rotary motion of a drill into a reciprocating motion for driving a saw blade. The rotating parts are positioned at a maximum distance from the reciprocating spindle to give the device the maximum degree of eccentricity with respect to the axis. This arrangement minimizes the force necessary to hold the saw and prevents rotation of the housing should the saw be released from the operator""s hands.
U.S. Pat. No. 2,793,661 discloses a power driven reciprocating saw unit for converting a power drill into a saw. The device converts the rotary motion of the drive shaft into a reciprocating motion by means of a pivoting cylinder that is attached to the-drive shaft.
U.S. Pat. No. 3,260,289 discloses a saber saw attachment for a power tool, such as a hand drill. A rotating shaft is attached to a piston at one end, and to the drill drive shaft at the other end. The shaft has a circumferential groove for receiving a ball bearing. As the shaft is rotated, the groove and ball bearing cause the shaft to reciprocated back and forth, thereby driving the piston.
U.S. Pat. No. 3,585,719 discloses a power tool for converting the motion of a rotary power source, such as a drill, into a reciprocating motion. The device can hold a variety of different cutting blades including hacksaw blades and edge trimmers. A rotating power shaft has inclined wobble plate that is connected to a reciprocating spindle. The entire tool is rotatable 360 degrees in relation to the rotary power source.
U.S. Pat. No. 3,876,015 discloses a power tool attachment that converts rotary to reciprocating motion for portable power tools. The attachment is secured to the power tool by means of an adaptor lock plate that is attached to the front of the power tool.
U.S. Pat. No. 4,841,643 shows a drill powered saber saw comprising a stationary support for supporting a power drill, and a flexible power transmission cable for connecting the saber saw attachment to the drill.
U.S. Pat. No. 4,494,463 discloses a sawing device attachable to regular electric drill comprising a spiral gear drive mechanism which converts the rotary motion of the drill into reciprocating motion.
U.S. Pat. No. 5,050,307 discloses a wobble plate drive that is mounted on a rotating shaft and has a drive arm engaging a reciprocating spindle so as to restrain the spindle from rotation.
U.S. Pat. No. 5,566,458 discloses a clutch mechanism for reciprocating saws comprising a spring biased gear which provides slippage between the motor and the drive shaft if there is binding of the reciprocating spindle.
U.S. Pat. No. 5,595,250 discloses a drill accessory for converting a power drill into a reciprocating saw having a blade which can be adjusted for several different cutting depths.
U.S. Pat. No. 5,607,265 discloses a reciprocating attachment for hand drills. The reciprocating attachment uses a grooved shaft for changing the rotation of the shaft of the drill to a reciprocating motion necessary to power a saw blade.
None of the above inventions and patents, taken either singularly or in combination, is seen to describe the instant invention as claimed. Thus a drill powered saw solving the aforementioned problems is desired.
In view of the foregoing limitations of the drill powered reciprocating saws described in the prior art, the present invention provides an improved reciprocating saw having an automatic safety mechanism that will disengage the saw""s drive mechanism and prevent the saw from rotating should the operator loose his or her grip on the saw housing, or should the drill be activated without the saw housing being gripped by the operator.
The invention comprises a reciprocating saw having a housing that is ergonomically configured to be gripped by a person""s hand. A handle is rotatably attached to the housing and may be rotated around the housing axis by loosening a clamp. A motor drive shaft for connecting to a power drill is mounted in the housing. The drive shaft is connected to a jackshaft by a safety gear assembly. One end of the drive shaft is attached to the housing by a spring and slide bearing which biases the drive shaft to a position where the gear assembly is no longer engaged, and therefore, no power is imparted to the jackshaft. The gear assembly is engaged by pulling the housing toward the drill along the axis of the drive shaft. When the gear assembly is engaged, the jackshaft drives a wobble plate which converts the rotational motion to reciprocal motion. The wobble plate is attached by a drive arm to a tubular spindle which drives a saw blade.
Accordingly, it is a principal object of the invention to provide a reciprocating saw that attaches to a power drill and converts the rotary motion of the drill into reciprocal motion.
It is another object of the invention to provide a drill powered reciprocating saw having a safety gear assembly which prevents the saw from rotating should the operator loose his or her grip on the saw housing.
It is a further object of the invention to provide a drill powered reciprocating saw a having a vibration insulating system which isolates the drive shaft from vibration caused by the saw""s reciprocating action.
Still another object of the invention is to provide a drill powered reciprocating saw having an ergonomically shaped housing to provide a comfortable grip for the hand.
It is an object of the invention to provide improved elements and arrangements thereof for the purposes described which is inexpensive, dependable and fully effective in accomplishing its intended purposes.
These and other objects of the present invention will become readily apparent upon further review of the following specification and drawings.